1. Technical Field
The present application relates to a lighting power supply device, and more particularly to a power supply circuit for LED lighting.
2. Description of the Related Art
Light emitting diode (LED) is growing in popularity due to decreasing costs and long life compared to incandescent lighting and fluorescent lighting. Recently, a number of LED lighting apparatuses have been designed to replace the halogen apparatus, as well as other traditional incandescent or fluorescence lighting apparatuses. In some places such as exhibition halls, jewelry stores, museums, supermarkets, and some home lighting, such as large villas, will use a lot of strip LED lamps. Moreover, in addition to lighting equipments, such as general traffic lights, billboards, motor-lights, etc., also use light-emitting diodes as light source. As described above, for the light-emitting diodes as a light source, the advantage is power saving, and the greater brightness. Therefore, the use has been gradually common.
As well known, power supply, which affects the life of LED lamps, as one of the most important factors, is also the object of concern. General LED power supply has output short protection circuit. The output short protection circuit may means that the power supply outputs very low system input power or low frequency power when the short circuit occurs. And after the withdrawal of the short circuit, the power supply can automatically return to normal work. However, with the increase of energy-saving awareness and light distribution requirements, a current-sensitive components, such as MOS tube, may be electrically connected in series between the power outputs and the LED lamp load. Therefore, when the LED light load is in short circuit, the output circuit must output a large impact current, and the impact current in the moment will reach tens to hundreds of amps. The impact current is often far more than the ultimate tolerance of the current-sensitive components. As a result, these current-sensitive components will be breakdown and the power supply fails.
Therefore, it is necessary to provide a power supply circuit for LED lighting having short circuit protection which makes it possible to prevent the power supply from failing.